#### Overview of this book

This book will teach you advanced techniques in machine learning with the latest code in R 3.3.2. You will delve into statistical learning theory and supervised learning; design efficient algorithms; learn about creating Recommendation Engines; use multi-class classification and deep learning; and more. You will explore, in depth, topics such as data mining, classification, clustering, regression, predictive modeling, anomaly detection, boosted trees with XGBOOST, and more. More than just knowing the outcome, you’ll understand how these concepts work and what they do. With a slow learning curve on topics such as neural networks, you will explore deep learning, and more. By the end of this book, you will be able to perform machine learning with R in the cloud using AWS in various scenarios with different datasets.
Title Page
Credits
Packt Upsell
Customer Feedback
Preface
Free Chapter
A Process for Success
Linear Regression - The Blocking and Tackling of Machine Learning
Logistic Regression and Discriminant Analysis
Advanced Feature Selection in Linear Models
More Classification Techniques - K-Nearest Neighbors and Support Vector Machines
Classification and Regression Trees
Neural Networks and Deep Learning
Cluster Analysis
Principal Components Analysis
Market Basket Analysis, Recommendation Engines, and Sequential Analysis
Creating Ensembles and Multiclass Classification
Time Series and Causality
Text Mining
R on the Cloud
R Fundamentals
Sources

## Model selection

What are we to conclude from all this work? We have the confusion matrices and error rates from our models to guide us, but we can get a little more sophisticated when it comes to selecting the classification models. An effective tool for a classification model comparison is the Receiver Operating Characteristic (ROC) chart. Very simply, ROC is a technique for visualizing, organizing, and selecting classifiers based on their performance (Fawcett, 2006). On the ROC chart, the y-axis is the True Positive Rate (TPR) and the x-axis is the False Positive Rate (FPR). The following are the calculations, which are quite simple:

TPR = Positives correctly classified / total positives

FPR = Negatives incorrectly classified / total negatives

Plotting the ROC results will generate a curve, and thus you are able to produce the Area Under the Curve (AUC). The AUC provides you with an effective indicator of performance, and it can be shown that the AUC is equal to the probability that the observer...